2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/188095We compute complete spectra of the staggered lattice Dirac operator for quenched SU(3) gauge configurations below and above the critical temperature. The confined and the deconfined phase are characterized by a different response of the Dirac eigenvalues to a change of the fermionic boundary conditions. We analyze the role of the eigenvalues in recently developed spectral sums representing the Polyakov loop. We show that the Polyakov loop gets its main contributions from the UV end of the spectrum.Typo fixed, to appear in Physics Letters BHigh Energy Physics - LatticeHigh Energy Physics - PhenomenologyHigh Energy Physics - Theorytext